Woody composition and structure of upland forest at carpenter park nature preserve: Implications for management

Background/Question/Methods

Sitting nearly in the geographical center of the state of Illinois and along the north bank of Sangamon River, Carpenter Park Nature Preserve contains one of the largest contiguous swaths of high quality old-growth, oak-hickory forests in central Illinois. As important habitat for many local wildlife species, this preserve also provides critical habitat for Neotropical migrants which are experiencing statewide declines due to habitat loss. While large oaks still dominate the forest canopy on the uplands, seedling and sapling age classes have become dominated by other species. Prescribed burns, coupling with selective thinning, have been considered necessary to restore the quality of upland forest of Carpenter Park by improving the lighting conditions conducive to oak recruitments. Every fall from 2004 to 2010, the upland forest of Carpenter Park was sampled by using the point-quarter method.  A major aim of this on-going sampling effort is to help assess the effectiveness of the management program. 

Results/Conclusions

While Quercus alba, Q. velutina, and Q. rubra still dominate the canopy layer according to their respective importance values throughout the 7-year sampling period, they were almost non-existent at the subcanopy level. Although they had lower importance values than oaks, Sassafras albidum, Carya cordiformis, and Celtis occidentalis were relatively common at the canopy level. S. albidum was the dominant species in the subcanopy layer while other subcanopy species of significance included C. cordiformis, C. occidentalis, Prunus serotina, Ulmus americana, and Asimina triloba. A. triloba shows growing dominance in the subcanopy level during the sampling period, which almost rivals S. albidum. The increasingly highly shaded environment in the subcanopy level creates difficult conditions for oak regeneration. Burning alone can lead to re-sprouting of A. triloba, and hence its growing dominance. The sampling results from the past 7 years suggest that selective thinning is critical for a successful restoration of upland forest of Carpenter Park.